(1) Field of the Invention
The present invention is directed to the production of wetting agents in pesticide formulations for use in agricultural applications. The invention is directed towards both method of manufacture, products produced and incorporation of said compositions into agricultural formulations thereby.
(2) Description of the Prior Art
Pesticide formulations used in agricultural formulations generally encompass herbicides, insecticides, fungicides, and rodenticides. The most popular forms of application of such formulations include emulsifiable concentrates, flowables, wettable powders, and water-dispersible granules. Emulsifiable concentrates are produced by dissolving the pesticide and the emulsifying agent in a water-insoluble organic solvent which is diluted with water at the time of use to form a stable suspension for spraying. Flowable formulations are dispersions of solid particles in a liquid, usually water, in which the solid has little or no solubility. A wetting agent concentration of around 2% is usually added to get the dry pesticide into the water phase for dispersion.
The wettable powder formulation is similar to the flowable formulations, except that the pesticides are pre-granulated with a dispersant and a wetting agent into small composite particles. The resulting small particle granules readily wet and disperse when added to water.
The water-dispersible granule formulations are formed by granulating mixtures of the pesticide with a wetting agent and a dispersant. A clay binder is often added to allow formation of large particles that can readily disintegrate and disperse in water.
In the past, a large majority of all pesticides were sold as emulsifiable concentrate formulations. Recently, however, with more governmental restrictive control imposed on unnecessary organic oils in pesticide formulations, water-dispersible granule formulations have been replacing the emulsifiable concentrate formulations. This greatly increases the market potential and demand for oil-free wetting agents and dispersants necessary for proper formulation of wettable powders or water-dispersible granules.
For example, U.S. Pat. No. 4,618,450 teaches amino sulfonic acid derivatives of carboxylic acids as emulsifiers, thickeners and dispersants in aqueous systems. Unfortunately, the products are themselves not oil-free, and the aqueous systems to which they are applied are taught to contain an oil phase ("diluent oil"). The present invention, on the other hand, is directed to oil-free wetting agents for application in aqueous systems with only a water phase.
Also, pesticide compositions have included lignin compositions as dispersants and napthylene sulfonates, ethoxylated alcohols, or tall oil fatty acid-derived materials as wetting agents. One such wetting agent product, a sulfonic acid derivative of tall oil fatty acid such as produced as a by-product of the kraft wood-pulping process, is taught in U.S. Pat. No. 3,986,979. Although compositions as this work acceptably as wetting agents, the reaction creates hydrogen chloride as a by-product, resulting in a highly corrosive atmosphere for reaction equipment, thereby reducing the life of the equipment.